The present invention relates to a door locking mechanism for locking and unlocking coke oven doors of the type wherein in the locking position the door body is held in contact with a door frame by spring pressure and by a locking bar which extends behind attachments or hooks of the door frame, the locking bar being pivoted into the locking position about a bolt which is screwed into an opening of the door body, wherein a sleeve element surrounding the bolt is inwardly axially displaceable for the purpose of releasing the locking bar from the locking position, wherein during its axial inward displacement, the sleeve element releases the spring pressure between the locking bar and the door frame, and wherein the spring pressure and the position of the locking bar with respect to the locking bar hooks can be adjusted.
A door locking mechanism of this type is shown by Grossinsky: Handbuch des Kokereiwesens [Manual of Coking Practice[, 1955 Volume I, page 238, FIG. 117. The bolt of this known door locking mechanism has at the front end thereof a collar which is contacted by the outer surface of the sleeve element. The bolt is threaded by means of which the bolt can be axially displaced by rotating the bolt within a further sleeve element which surrounds the bolt. Such further sleeve element has an external thread by means of which it is possible to axially adjust the further sleeve element and, therewith, also the entire spring arrangement and the position of the locking bar with respect to the attachments or hooks of the door frame. The spring pressure is provided by a cup spring which is positioned between a shoulder of the further sleeve element and a pressure plate, which contacts the inner surface of the first sleeve element and the locking bar. The spring pressure is applied by rotating the bolt with respect to the further sleeve element, thereby determining the axial position of the first sleeve element. The relative position of the locking bar with respect to the locking bar hooks is adjusted by rotating the further sleeve element in the threaded opening of the door body. However, the further sleeve element is accessible to rotation only when the bolt is completely unscrewed and when the first sleeve element is removed.